Musical instruments such as flutes, saxophones, and piccolos have tone holes. Forming these tone holes is a craft often involving numerous steps, the use of different machinery, and different jigs, fixtures, and tools.
In one example in accordance with the state of the art, a computerized numerical control (CNC) machine is used to drill pre-opening holes in the flute body. The holes could also be punched. The flute body is removed from the CNC machine and taken to an extrusion station. There, an arbor is inserted into the flute body and a pulling ball is loaded in the arbor. The flute tube is then slid over the loaded arbor. The flute and loaded arbor are then placed on an extrusion machine which contains a die or “chimney” directly over the hole in the flute tube and the loaded pulling ball. A shaft is then connected to the pulling ball through the hole drilled in the flute body. The shaft is connected to the extrusion machine which then rotates the pulling ball and urges it out of the flute body through the chimney to form the tone hole. The remainder of the tone holes are formed in this same way. Next, the flute body is returned to the CNC machine where the tops of all the tone holes are machined flat (“faced”) to render them level. Finally, the edges of the tone hole are rolled out to finish the tone hole.
Thus, forming tone holes requires the use of different machinery, different jigs and fixtures, and different tools resulting in a time consuming and costly process. Also, since the configuration of the tone holes is critical, there is the possibility of inaccuracies and intolerances where certain dimensions of the tone hole do not meet specifications each time the flute body is moved and/or fitted with a different arbor.